Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Nebiker S., Caldwell C., Knight R.

Understanding the relationship between the ecological health of a stream and its flow is critical for resource managers to develop effective water management plans that address multiple and often conflicting uses throughout a river basin. Since management objectives must be considered in a basin-wide context, it is important to conduct regional analyses of the relationship between streamflow and riverine ecosystems that account for differences in physiography, land use, and topography. Further, for the flow-ecology recommendations to be scientifically credible, they must be derived from measured data. However, the effort required to do these analyses on a regional scale, let alone on an individual river segment, can be prohibitive.

Throughout the eco-flow assessment process, decision makers must be involved so as to promote collaboration between stakeholders and to identify the trade-offs between varying management strategies. To that end, it is helpful to (a) distill the underlying analysis down to the most ecologically-relevant flow criteria so that flow-management models can quickly generate results and (b) distill the resulting environmental metrics down to an easily understood concept like fish diversity, i.e., number of fish species. For decades, the integration described above has been elusive. This presentation introduces a framework to operationalize flow-ecology relationships into decision-support systems of practical use to water-resource managers, who are commonly tasked with balancing multiple competing socioeconomic and environmental priorities. We illustrate this framework using a case study from the Tennessee River Basin - one of the most ecologically diverse basins in the United States - whereby fish community responses to various water-management scenarios were predicted in a partially-regulated river system at a local watershed scale. The water-allocation modeling framework used - OASIS - is flexible, transparent, and allows for quick screening of management scenarios which positions it to be used in a collaborative setting with watershed stakeholders.